Sources: iPhone4 alone, iPhone4 with PA2V2 using LOD, various computers using Audioengine D1 DAC and the D1's headphone out.

First impression: Very lean bass, slightly hollow mids, strong treble. The very lean bass became less lean after giving the earpads some time to develop a better seal. Based on prior experience with low-cost plastic earpads similar to the HD-280's, I think these earpads will always need a minute or two to get the best bass seal possible. If I can find replacement earpads that are covered with a better quality material, it might improve the upper bass and lower midrange, if it doesn't boost the lower bass too much.

Running some sweep frequency tones, I note that the HD-280 is recessed somewhat from the upper bass through 200 hz or so, which makes the sound above 300 hz seem emphasized and contributes to the impression of a slight hollowness on first listen. The sensation of hollowness goes away pretty quickly, but male voices may seem slightly distant or weak in some cases. Another side effect of the recessed upper bass is when listening to a lot of tracks I'm familiar with, the lower bass seems to hit a lot harder. Moving up past the mids to the treble, I don't find anything remarkable until I get to about 7 khz, where the output seems stronger than average. I also hear some emphasis around 9 khz, and I suspect that the strong output at these frequencies may be a contributor to the slightly "zingy" or "tizzy" treble on some tracks. Despite the fairly strong treble, sibilants and other treble harshness seem to be less of a problem than what's average for my other hi-fi headphones with strong treble.

The HD-280 very nearly qualifies as portable by my standards, i.e. being able to wear a headphone around my neck all day when not in use. But even though the earcups pull down just far enough and fold flat on my chest, the feeling is claustrophobic there, and the long, heavy, non-detachable coiled cable is the negative deciding factor. The earpads aren't especially soft, and are covered in a very low-cost plastic. The pads are circumaural (around the ear) and are large enough to not touch my ears. I think a person would have to have very large ears to feel cramped by the HD-280's earpads. The clamping force is very strong, unusually so, and until a person gets accustomed to it they might experience a headache or two. In fact, if an HD-280 user does get used to the clamping force, the long-term comfort should be good since there are no other issues with pinching or lack of flexibility in getting a good fit. After using Beyer's DT-48 headphones, getting used to the HD-280 was no problem for me.

The HD-280 feels light for a full-size headphone, and appears to be all plastic. The cable is terminated in a standard 3.5 mm miniplug with threads for a screw-on 6.35 mm adapter (included in the packaging). Nothing else is supplied. In spite of the HD-280's low price and plastic build, the appearance is decent, the earpads, headband, and cable are replaceable, and the overall sound quality is very good given the slight de-emphasis of the upper bass and lower midrange as noted above. In other reviews I've done I've included the following music examples with comments about how the headphones sound with each track. My suggestion is instead of reading each one as an absolute unto itself, you could compare my notes here to other reviews and see how the HD-280 compares with each individual track.

Bauhaus - Bela Lugosi's Dead (~1980): Strong midrange sound effects - this is a good worst-case test for resonant-type sounds in the most sensitive midrange area. Handled very well by the HD-280.

Beethoven Symphony 9, Solti/CSO (1972): Very good overall sound. Of special note for this headphone are the bass impacts beginning around 10:30 of the fourth movement. Those impacts are unusually strong with the HD-280.

Blues Project - Caress Me Baby (1966): Rarely mentioned, but one of the greatest white blues recordings ever. The loud piercing guitar sound at 0:41 into the track is a good test for distortion or other problems. Handled very well here.

Boz Scaggs - Lowdown (1976): Good sound quality - this is a great test for any nasality in the midrange. Handled well by the HD-280.

Buffalo Springfield - Kind Woman (~1968): A Richie Furay song entirely, rarely mentioned, but one of the best sounding rock ballads ever. This will sound good on most headphones, and it sounds very good with the HD-280.

Cat Stevens - Morning Has Broken (early 70's): A near-perfect test for overall sound - this track will separate the best sounding headphones from the lesser quality types. Nothing specific, except that almost any deviation from perfect reproduction will stand out with this track. Sounds very good on the HD-280.

Catherine Wheel - Black Metallic (~1991): Goth with industrial overtones - I like this since it's a great music composition and the sound effects are smoothly integrated into the mix. This may sound distorted or mushy with some headphones, but the HD-280 renders the deliberate instrumental distortions clearly.

Def Leppard - Bringin' On The Heartbreak (1981): MTV goth/pop/metal at its best - good ambience and high energy - the better headphones will separate the details and make for a good experience. Lesser quality and the details tend to mush together. The HD-280 plays this very well.

J.S. Bach - E. Power Biggs Plays Bach in the Thomaskirche (~1970): Recorded on a tracker organ in East Germany, the tracks on this recording have the authentic baroque sound that Bach composed for, albeit the bellows are operated by motor today. The HD-280 plays the tones seamlessly through the upper limits of the organ, which cover nearly the full range of human hearing. Of special note are the pedal notes - tracker organs have low-pressure pipes and don't typically produce the kind of impact around 30-35 hz that modern organs do. A headphone that's lacking even a little in the low bass will sound especially bass-shy with this type of organ, but the HD-280 delivers the full experience of this music.

Jamming With Edward - It Hurts Me Too (1969): Intended originally as a test to fill studio down time and set recording levels etc., this was released a few years later for hardcore Rolling Stones fans. Although not as good technically in every aspect as the Chess studio recordings of 1964, and in spite of the non-serious vocals by Mick Jagger, this rates very high on my list of white blues recordings, and sounds absolutely delicious with the HD-280.

Jennifer Warnes - Rock You Gently (1992?): The strong deep bass percussion at the beginning of this track has been cited as a test for weakness or distortion in certain headphones. The HD-280 plays those notes with good impact and control. Having played this track a number of times now, I'm highly impressed with the HD-280's bass reproduction and detail throughout the track.

Jimmy Smith - Basin Street Blues (early 60's): This track has some loud crescendos of brass and other instruments that don't sound clean and musical on some headphones. The HD-280 provides very good reproduction. Listen particularly to the second crescendo at 15 seconds in, for maximum detail effect. I'd like to emphasize that these crescendos are probably the worst-case test I have for instrumental separation and detail, and the HD-280 plays them well.

Ladytron - Destroy Everything You Touch (~2009): Featured in The September Issue, this song has heavy overdub and will sound a bit muddy on some headphones. Sounds good with the HD-280.

Milt Jackson/Wes Montgomery - Delilah (Take 3) (1962): The vibraphone is heavily dependent on harmonics to sound right, and the HD-280 plays it very well.

Pink Floyd/Dark Side of the Moon - Speak To Me (1973): Strong deep bass impacts will be heard and felt here.

Rolling Stones - Stray Cat Blues (1968): Dirty, gritty blues that very few white artists could match. On some headphones the vocals and guitar lack the edge and fall more-or-less flat. If you're a really good person, playing this song will probably make you feel nervous and uneasy.

Tony Bennett - I Left My Heart In San Francisco (1962): Frank Sinatra's favorite singer. Highest recommendation. With some of the best headphones, the sibilants on this recording are very strong, but they're not bad with the HD-280.

Yeah, the earpads on those headphones give you a little bit of a "wtf?" reaction when you first encounter them. It's like "no, those belong on $25 around-ears".

Otherwise I thought they were really fun rock headphones when I tried out my buddy's pair. Gear used there was a Technics SL1200Mk2 w/ Shure M95 cart and big old Kenwood receiver playing The Big Come Up by The Black Keys. It really did accentuate the emphasis on the treble you noticed. On that recording it damn near almost hurt my ears.

But yeah, fast and fun if not a little unrefined. Great for a first pair of headphones I think. I can also see/hear why a lot of schools with a/v editing courses provide them to students.

Most of the treble emphasis and lower midrange dip eases out after having them on for awhile, not so much because you get used to them, but because those horrible earpads eventually form a minimal seal to your head, which improves the bass, which in turn diminishes the effect of the strong highs.